DNAS servers going offline will only affect games that still uses the service, but it won't affect Outbreak File #1 and File #2 because there's the DNAS check skip patch, right?

It would affect Outbreak 1-2. Sure, those that have a bypass patch would not be affected at all but not everyone does. It stands right now we have a very large population who play with the traditional NTSC-J PS2-DVD console setup. With DNAS offline this setup is no longer viable to work for them. We are trying to keep it so these users or anyone can do the traditional setup. We want as few barriers of entry as possible.